Are you sure that all HW the same? (for example G-sensor, GPS support etc.)
If so - the A118C2 FW is most recent FW also for version 1, and it'is worth to use it.
Now I can confirm: I successfully installed A118C2 20161008 FW on A118c, and after that also successfully downgraded back to Blueskysea 20150403. Didn't test outside.